John alves



(No Model.)

J. ALVBS. MEANS FOR SUPPLYING HOT AIR T0 BOILER FURNACES.

Patented Aug 25, 1896.

Ml/ v M PATENT FFICE.

JOHN ALVES, OF MELBOURNE, VICTORIA.

MEANS FOR SUPPLYING HOT AIR T0 BOILER-FURNACES.

SPECIFICATION forming part of Letters Patent No. 566,645, dated August25, 1896.

Application filed June 18, 1896. serial No, 553,216. (No model.)

To all whom it may concern:

Be it known that I, JOHN ALvEs, engineer, asubject of the Queen of GreatBritain, residing at No. 17 Market Buildings, Flinders Lane, Melbourne,in the British Colony of Victoria, have invented an Improved Method ofand Apparatus for Supplying Hot Air or a Mixture of Hot Air and Steam toBoiler and other Furnaces, of which the following is a specification.

This invention relates to improved means for supplying hot air toboiler-furnaces, and has for its object to enable a maximum heatingefiect to be obtained from the fuel.

The invention consists in the arrangement of an outer tube orsuctiondiue around the smoke-stack or chimney, so that said flue com}municates with a hollow bridge-wall at the back of the fire-box. Saidouter tube or suction-flue is fitted with a number of spirallyarrangedplates forming a spiral passage around the chimney-stack, so that theair passing down the same will be thoroughly mixed and heated beforebeing delivered into the furnace.

The hollow bridge-wall above referred to is formed with a grating alongthe front of its lower end and has a hollow perforated portionprojecting forwardly into the furnace. The bridge-piece is protectedwith fire-brick and a valve or damper is provided for regulating the airsupplied to it.

Having now generally described and ascertained the nature of myinvention, I will proceed to more particularly describe it with the aidof the accompanying drawings, wherein- Figure 1 is a side elevation of alocomotiveboiler fitted according to my invention, the fire-box beingshown in section. Fig. 2 is a vertical transverse section on the line 22 of Fig. 1. Figs. 3 and a are respectively a vertical sectional viewand a view in side elevation, showing a slight modification.

Referring to Figs. 1 and 2, the referenceletter A indicates the outertube or suctionflue,which is arranged around the smoke-stack or chimney(3, running along each side of the boiler and communicating by means ofa vertical passage with the hollow bridge-wall D of the furnace, while aa indicate the spirallyarranged plates which operate to form a spiralpassage around the chimney B in the space between it and the outer tubeA, for the purpose described.

In order to carry out my invention, the fire box E must be closed in,excepting where it communicates with the lines 0, leading to the tube A,so as to exclude any air except that which has passed around the chimneyB and along the sides of the boiler and thereby been heated. A valve dis fitted in the passage leading from the fines O to beneath thegratebars 6 to regulate the admission of the heated air to the hollowbridge-wall and the ash-pit, respectively, said valve being preferablyso arranged as to insure about one-third of the air passing to thehollow bridge-wall D and the remaining two-thirds through the firebars.

In the arrangement shown in Fig. l the flues 0 pass down under theboiler, at the rear end thereof, in front of the fire-box E. In somelocomotives, however, where the crank travels close up to the fire-boxand there is not sufficient space to admit of this arrangement, thefines C may be constructed as shown in Figs. 3 and 4:, that is, they maybe extended back onto the fire-box and thence down the sides thereof,from whence they communicate with the hollow bridge-wall and the ash-pitin the manner before described. I prefer to provide two spiral plates ataround the chimney B and to arrange each of the passages so formed thatit will communicate with each of the tines 0.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is--- In a boiler-furnace, the combination of thesmoke-stack, a suction-tube encircling the smoke-stack, a partitionarranged to form a spiral passage between the smoke-stack and thesuction-tube, said spiral passage opening at its top into the atmosphereto form an entrance for natural draft, fiues arranged on each side ofthe boiler and communicating at their forward ends with said spiralpassage, a vertical flue connecting the rear end of said does with therear end of the ash-pit, a hollow bridge-wall arranged in the fire-boxand communicatin g at its lower end with said vertical flue, and a valvefor regulating the admission of the air heated in the spiral passage tothe hollow bridge-wall and the ash-pit respectively, substantially asdescribed.

JOHN ALVES.

'Witnesses EDWARD Warnns, EDWARD WATERS, Jr.

